Electronic displays are commonly used to portray data in the form of visual information to be acted upon by the user. The information is typically derived from a computer and used interactively to conduct data and word processing, advertising signage, as aerospace instruments, to fly airplanes, to control machines, etc. Today, LCDs are the leading technology for such displays. LCDs are electronic FPDs that have great industrial utility. Methods for resizing FPDs are described in U.S. Pat. No. 7,535,547, titled “Customized Electronic Display and Methods of Customizing the Physical Size and/or Shape Thereof,” which is hereby incorporated herein by reference in its entirety.
To more easily understand the nature of the problem addressed by the present invention, a brief description of the structure and operation of an LCD as an example of an FPD and of resizing an LCD follows. For a more detailed description, the reader is referred to the above-referenced U.S. Pat. No. 7,535,547.
An LCD is made from two substrates (20) of transparent material, typically glass among other things, with a thin film of liquid crystal material sealed between the two substrates (20). Spacers may be placed in between the substrates (20) in a precise manner, thus forming a uniformly spaced cell. The cell is sealed with a perimeter seal (25). A simplified schematic of a typical LCD panel is shown in FIGS. 1a and 1b of the above-referenced U.S. Pat. No. 7,535,547. The display's active area is defined by electrodes on the inside of the substrate in the cell area organized to address picture elements (pixels). There are many pixels electrically stimulated (controlled) to create images. Each pixel is controlled by electrodes (30) that continue outside of the seal area to the edge of the substrate(s) (20). The electrodes (30) are connected to external electronics that in turn are connected to a computer or similar electrical stimulus. A pixel is formed at each intersection of a row and column line and there may be other electrical components at the intersection such as thin film transistors (TFTs) and capacitors and other conducting lines such as ground potential lines. Typically, the electrodes (30) are thin film metal conductors organized in lines of rows and columns with hundreds of row and column electrodes running the full length and width of the substrate(s) (20), wherein one row electrode line and one column electrode line are associated with each pixel in a matrix-like organization. Typically, in an active type LCD, all of the row and column electrodes (30) are on the inside surface of one of the substrates (20), and a common ground plane (35) is on the inside surface of the opposing substrate. The liquid crystal material and spacers are in between the electrodes (30) and the ground plane (35). All of the row, column and ground plane electrodes are insulated from one another except at unique points to facilitate the operation of the display. The liquid crystal film, spacers, substrates and the sealant enclosing the cell, are all dielectrics.
When a display is resized, the cell is cut through the substrate, thus transitioning the image display area, perimeter seal and all of the electrodes at the cut edge (55). The LCD is then cut and completely separated into a target portion (5) and a waste portion (not shown). When this occurs, all of the thin film electrodes (30) may not separate exactly along the cut edge (55). In other words, the conductor lines (30) and the ground plane (35) are disturbed by the resizing process, thus possibly causing undesired electrical contact in some manner. In the simplest example, some electrodes (30) may tear loose from the substrate (20) at the cut edge (55) and make physical contact with each other or with the ground plane (35), thus causing an undesirable electrical short circuit. Examples of conductor lines (30) shorting to the ground plane (35) are shown in FIG. 1, labeled specifically as 30-s1 (representing a line that became dislodged from the substrate) and 30-s2 (representing a line that became bent). Application of the resizing sealant (45) and the inevitable fluid motion may cause additional shorts. The exact detail of how the short circuits occur is not significant, as any short at the cut line will adversely affect the image area (40) of the display. The electrodes in question may be very close such that they may short at a later time due to contamination or motion at the location in question.
Such electrical shorts may undesirably be cemented and bound together when the cell is resealed. In that case, when the LCD is tested, the pixels connected to the shorted row or column line(s) (30) will not respond properly to the image signal and will act as if the pixels associated with the shorted electrode have failed. Typically, this means the image would appear to have a line of failed pixels as a result of a shorted conductor line extending from the point of the short circuit along the shorted line into the image area (40). An example showing the location of an image failure resulting from a shorted conductor line (30-s1) is shown symbolically as a row of x's (50) in FIG. 2. Multiple shorted lines may exist simultaneously. The failed pixels may only extend a short distance from the cut edge in the case of very weak shorts. Or not at all because the short is so weak or not quite complete such that its effect or potential effect is not ramified in the image. Many types of shorts can occur in many ways or at different times. The exact nature of the short or details of the short are not critical, since in such cases the resized target display would be defective unless the resized image area was restored to eliminate the resulting failed pixels in the image that was caused by the short or belated short at the cut edge (55).
There is thus a desire for a method to remove the short or shorts caused by the resizing process, and to restore the failed pixels in the image of a resized FPD caused by the shorted electrical line(s) at the cut edge. Further, it is recommended to perform steps to ensure the short or shorts or belated shorts are permanently removed and do not reoccur during the operational life of the resized display.
The methods described herein may be applied to FPDs other than LCDs, such as Organic Light Emitting Diode displays, electrophoretic displays, electroluminescent displays, etc.
The shorted electrodes via the pixel arrangement as dictated by the electrode arrangement affect the image. Typically when a short does occur the pixels and electrodes are in a straight line as discussed in the example herein. However, that is not always the case.